Medical error is a leading cause of death in the United States. Sleep deprivation has been proven to significantly impair performance and increase the risk of error in industrial settings, but health care has been slow to adopt work hour reforms. Physicians-in-training still routinely work up to 30 hours in a row. We recently found that interns working a traditional schedule in two ICUs made 36 percent more serious medical errors and 5 times as many serious diagnostic errors as interns whose consecutive work was limited to 16 hours. Despite this substantive improvement, however, full implementation of a reduced work schedule has not occurred, even in the units where our intervention proved effective. Barriers to broadly implementing change have included our prior study's focus on interns rather than all house staff, and perceived problems with our initial intervention signout system. To more effectively implement reduced work hours for physicians, while addressing the limitations of our prior intervention study, we propose the following: [unreadable] [unreadable] 1. To implement two new house staff work schedules in a MICU and CCU, which will eliminate extended shifts for all interns, junior residents, and senior residents in these settings; [unreadable] 2. To test the hypothesis that compared with a traditional schedule, house staff sleeps as well as serious medical error rates will improve in a new CCU schedule that eliminates extended shifts for all interns and senior residents, but retains a traditional rounding and house officer staffing structure; [unreadable] 3. To test the hypothesis that house staff sleep and serious medical error rates will likewise improve in a restructured MICU that eliminates extended shifts, but also dramatically alters staffing, sign out, and [unreadable] rounding systems to support shorter work hours, including the initiation of twice-daily team rounds. [unreadable] [unreadable] Our proposed before-after study of two distinct schedule implementation strategies will advance knowledge of how best to reduce work hours while minimizing errors due to care discontinuities. We will determine serious error rates using our established four-pronged detection method that includes direct, continuous observation of house staff by physicians, followed by rigorous review of all incidents. Comparisons before and after implementing each system will yield information needed to develop an effective scheduling tool that can be widely disseminated to reduce physician work hours and improve patient safety nationwide. [unreadable] [unreadable]